The present invention broadly relates to stacking devices and, more specifically, pertains to a new and improved construction of an apparatus for producing stacks of printed products provided with a cover sheet.
Generally speaking, the apparatus of the present invention comprises a delivery conveyor for supplying printed products, a stacker arranged subsequent to the delivery conveyor and having at least two stacking wells or chutes individually supplied from above and deposition means for depositing one cover sheet on each produced stack.
Shipment of printed products, for instance newspapers, from the printing plant to large distribution centers is usually done in stacks. It is usual to provide each stack with a cover sheet upon which, for instance, the address of the distribution center and the number of copies included in the stack are indicated.
These cover sheets were heretofore either deposited manually upon the stack as it left the stacker or else so-called depositors were proposed which removed one cover sheet from a prepared packet of such cover sheets and deposited it upon the upper side of the stack as it left the stacker. Manual deposition is not able to keep up with the production capacity of modern stackers which, in turn, are adapted to the production capacity of modern rotary printing presses or rotogravure machines. The employment of depositors entails the disadvantage that the stack leaving the stacker must be temporarily halted in order that the cover sheet can be deposited thereupon, whereupon the stack must be again set in motion. This is detrimental to the stability of the stack since the stack is not yet tied or stabilized by other wrapping means. Furthermore, the outlets of the depositor must be adapted to the varying heights of the stacks leaving the stacker, which requires corresponding mechanical equipment expenditure.
In modern stackers, which--as already mentioned--are able to accommodate the continuous and high production capacity of rotary printing presses or rotogravure machines, two or more stacking spaces--also called stacking wells or clutes--are provided and are alternatingly supplied by a delivery conveyor. If the heretofore known depositors were employed in such stackers, then one depositor per stacking well would have to be provided which, quite apart from increased mechanical equipmebnt expenditure, would require more space.